Electrical engineering

A capacitor is broadly defined as two conductors that can hold opposite charges. It can be used as either a sensor or an actuator. If the distance and relative position between two conductors change as a result of applied stimulus, the capacitance value would be changed. This forms the basis of capacitive (or electrostatic) sensing.

A MEMS system, including sensors and actuators, invariably consists of mass and supporting structures. The supporting mechanical elements (membranes, cantilever, or suspensions) provide elastic restoring spring constants. Movement of the mass is impeded by collision with air molecules surrounding the mass. This constitutes damping, which is a velocity-dependant resistance force. As such, a MEMS system

Silicon, an element commonly found on sandy beaches and in window glasses, is the substrate of choice for building integrated circuits. Silicon belongs to a class of materials called semiconductors. which offers remarkable electrical characteristics and controllability for electronics circuits. Semiconductor silicon is the most common material in the MEMS field. Naturally, the electrical and

To following is a list of important issues to consider when evaluating an etching process. Etch rate. The speed of material removal is important. A higher etch rate translates into shorter etching time and greater manufacturing throughput. End point detection. Determining that a process step has finished is not as easy as it may sound.

A basic understanding of the fabrication technology for integrated circuit, which precedes that of MEMS in history, is necessary to understanding the micromachining process. A reader who is familiar with the basic microfabrication process of integrated circuits may skip this section. A fabrication process for integrated circuits generally involves many steps of material deposition, material

Plasma etching is a very prominent method of removing materials from a wafer surface. Since the process does not involve wet chemicals, it is often referred to as dry etching. The etching is carried out in a specialized process equipment called the plasma etcher. A chamber with two opposing electrodes is filled with a chemically

These galvanometers are of d’Arsonval type having a moving coil suspended between the pieces of a permanent magnet. When an alternating current is passed through the moving coil, an alternating deflecting torque is produced which makes the coil vibrate with a frequency equal to the frequency of the current passing. On account of inertia of

It consists of a single loop of thin phosphorbronze strip which forms the moving system. It is called a vibrator loop. The vibrator loop is situated in the field of a permanent magnet but when high sensitivities are required, highly saturated electromagnets are used. The vibrator loop is formed by passing the strip over an